1. Field of the Invention
The present invention relates to optical sensing systems for still cameras, and more particularly, to a sensing system with photoelectric sensors which are arranged in a strip pattern and are responsive to sharpness of focus of the objective in a reflex camera.
2. Description of the Prior Art
It is known that the objective of a photographic camera can be focused automatically by projecting an image of the sighted object at two different aperture angles onto each of two photoelectric receptors or sensors, which are arranged in a strip pattern.
From German Patent No. 1,263,325 it is further known that the light output of the sensors can be converted into a measure of the sharpness of focus of the camera objective. The signal obtained in this manner can either be fed to an adjustment motor which will reset the objective until sharp focus is achieved, (automatic focusing), or it can be fed to an indicating device which gives a reading of the focusing condition. In the latter case, the objective must be moved by hand in order to obtain a sharply focused setting (semi-automatic adjustment).